Nortel DMS-100 Series Maintenance Manual page 385

A carrier is placed temporarily system busy (SysB-T) or permanently system
busy (SysB-P). The state depends on the number of times the system
returned the carrier to service.
The carrier is set SysB-T if the carrier meets the following requirements:
A steady state alarm was raised for a carrier, excess bipolar violations
occurred, or the carrier exceeded the OL for frame losses or slips.
The
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not exceeded the OL for RTS.
If the same carrier exceeds its OL for RTS, it is set SysB-P and must be
manually returned to service.
The DMS-100 switch places a carrier OOS when the system raises an
LCGA. The DMS-100 switch RTSs the carrier when the alarm clears and
the frame is regained. Operating company personnel can place a limit on the
number of times a carrier is RTS. This limit prevents a carrier from
bouncing between SysB and InSv states for an amount of time that is not
limited. The default for the consecutive number of times the system can
return the carrier to service is 255.
A carrier remains in the SysB-T state until one of two events occur.
Operating company personnel can take manual action to return the
carrier to service. In this event, RTS sequence tests pass and indicate
that faults do not persist in the carrier.
The system also can take action to return the carrier to service. The
system returns the carrier to service when the carrier audit cannot find
alarms that persist in the carrier.
Operating company personnel must return a carrier in the SysB–P state to
service manually.
The ML, OS, and audit interval defaults for frame losses, BpV, slips, and
RTS appear in the following table.
command is in use with the carrier, but the carrier has
DMS-100 Family SMS Maintenance Manual XPM10 and up
Trouble isolation and correction 9-21